Medium severityauthentication
Power BI Refresh Error:
Failed to get access token by using service principal. ADAL Error: service_unavailable
What does this error mean?
The pipeline could not get an Azure AD token — the STS returned service_unavailable. This is a transient Azure AD outage; retry after a few minutes.
Common causes
- 1Azure Active Directory is experiencing a transient outage or service degradation
- 2The Microsoft identity platform endpoint is temporarily unavailable from the IR's network
- 3DNS resolution for login.microsoftonline.com is failing from the integration runtime
- 4A proxy or firewall is intermittently blocking requests to the Azure AD token endpoint
- 5The Azure AD tenant has reached a service limit or throttling threshold
How to fix it
- 1Wait and retry — service_unavailable from Azure AD is usually transient and resolves within minutes
- 2Add retry logic to the ADF pipeline: use retry settings on the activity (up to 3 retries with 30s delay)
- 3Check the Azure AD Service Health dashboard for any active incidents
- 4From the IR machine, test DNS: Resolve-DnsName login.microsoftonline.com
- 5Verify outbound HTTPS (port 443) to login.microsoftonline.com is not blocked by proxy or firewall